Compressing gas is a well known process. Typically compressors are used to compress a gas. Gas compression is for example part of a gas turbine process to generate power. US-A-2011/0088404 describes a process wherein air is compressed in a gas compressor. The compressed air is com busted with a fuel and the resulting hot process gas is expanded in an expander. The expander is coupled to a device to convert the rotational energy to power, e.g. electrical power. The energy required to operate the compressor is typically delivered by the rotational energy of the expander by a direct coupling of the compressor and the expander as shown in FIG. 1 of this publication. This publication also describes the use of a source of waste heat to be used to heat partially compressed air as obtained in the compressor. This heated air is used to generate additional power in a lower pressure expansion stage.
BE1016500 describes a process wherein air is compressed in several compression stages. The compressed air is used in a combustion turbine. Before being compressed the air is heated using heat recovery from the exhaust gas of the turbine.
US2011/036097 describes a rotary regenerative heat exchanger for heat exchange between a compressed gas and the exhaust gas of a combustor.
A disadvantage of a traditional gas turbine process as illustrated above is that a large compressor is required. A further disadvantage is that the energy to operate the compressor is provided by the rotational energy of the expanders of the gas turbine. Thus part of the energy obtained in the expanders is used for compressing the combustion air. This coupled system makes the gas turbine process expensive and less efficient. It is an object of the present invention to provide an alternative process for compressing a gas.